Method of recovering values from flue-dust.



PATENTED MAR. 12,1901,

R.BAGGALBY. METHOD OF RBGOVERING VALUES FROM PLUE DUST;

APPLICATION FILED. DBO. 6. 1 904.

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x s x x xxx PATENTBD MAR R. BAQGALEY; METHOD OF RECOVERING VALUES .FROMFLUE DUST APPLICATION FILED DEU- 6. 1904.

WITNESSES UNTT STATES PAENT ()FFTQE.

METHOD OF RECOVERING VALUES FROM FLUE-DUST.

Specification of Letters Patent.

it atenteoi March 12, 1907.

Application filed December 5, 1904. Serial No. 235,418.

To cbZZ whom it may concern:

Be it known that I, RALPH BAGGALEY, of Pittsburg, Allegheny county,Pennsylvania, have invented a new and useful Method of Recovering Valuesfrom Flue-Dust, of which the following is a full, clear, and exactdescription, reference being had to the accompanying drawings, formingpart of this specification, in which- Figure 1 is a cross-section of ametal-block converter in which my invention may be successfullypracticed. Fig. 2 is a cross-section of a Water-jacketed converter whichis also suitable for practicing my invention. Fig. 3 is a longitudinalsection of the water-jacketed converter having oil-burners.

The object of my invention is to provide a cheap and efficient'method ofrecovering practically all of the mineral values that are contained influedust, resulting from the smelting, calcining, and converting ofores, and more especially copperores.

It is well known that no satisfactory method at present exists for therecovery of metal values from flue-dust. In the treatment of copper oresthe present practice consists almost universally in mixing flue-dustwith some bonding agent or cement or in mixing flue-dust with fines orconcentrates, which after also being mingled with some bonding agent aremolded, usually by hand, into bricks and baked, or they may be briquetedby suitable machinery and then baked. In such form these bricks orbriquets are fed into the ordinary copper-smelting blast-furnace withores in the hope that they may thus reach the zone of fusion and becomesuccessfully melted and form a part of the molten matte. The cost ofthus treating flue-dust prior to the effort to melt it will approximateone dollar per ton. The wear and tear on the briqueting machinery isnecessarily heavy and expensive, because the quartzy nature of thematerial under treatment, and particularly of the fines andconcentrates, quickly cuts out the metal molds and dies with which thebriquets are pressed. The modern copper blast-furnace is purposely madehigh in order that a long travel may be provided between thecharging-fioor at which the charge enters and the level of the twyers atwhich it is melted. These furnaces are so operated that the charge willtravel slowly downward from the chargingfloor to the zone of actualfusion, and during this travel while heated red-hot it is subjected toenormous volumes of air-blast at low pressure as a means of calciningthe charge within the furnace itself before fusion. This constitutes aportion of the method followed in present practice to bring ores up to adegree of richness through calcination, so that when in the moltencondition they will yield a fifty-per-cent. matte, or at all events amatte not lower in grade than forty-five per cent. The present form ofsilica lining used in a converter cannot successfully handle a matte oflower grade, or, in other words, it cannot convert a matte of lowergrade into finished blister-copper with the silica that it is possibleto supply to the matte from a single lining. When briquets or hand-madebricks composed of flue-dust or of flue-dust mingled with fines andconcentrates are thus fed into a blast-furnace with ores, these alsobecome heated with the ore, and they are expected to travel in a red-hotcondition slowly from the charging-floor down to the zone of fusion, andduring the entire period of travel they are subjected to a strong blastof air. While some forms of ore may possibly maintain their integrityuntil the zone of fusion has been reached and may thus be reduced to amolten condition without serious mechanical loss, many kinds of ore, andparticularly those delivered into the furnace in a finely-divided-state,will have the fine particles quickly calcined, and being thus reduced inspecific gravity will be carried by the blast out of the stack and willfloat away, causing a heavy mechanical loss. Such mechanical loss of oreand loss from volatilization are notoriously large in-all silver-lead.smelters, so that vast systems of flues and dust-chambers are essentialin order to produce satisfactory commercial results. i

In the case of briquets or hand-made bricks composed of flue-dust,fines, or concentrates the situation and the resultant losses arepeculiarly aggravated because just as soon as they have been heatedred-hot in the furnace the bonding agent of whatever character becomesdestroyed. Hence each separate briquet in the furnace crumbles again todust, and in this form the blast carries it up the stack, only to beagain partially recovered in the dust-chambers and to be again briquetedand baked for another trial at melting. The carrying off of the dustthus becomes a continuous performance, and each time with heavymechanical losses and heavy losses in volatilization. The proportion offlue-dust that reaches the zone of actual fusion in the furnace in theform of either brick or briquets, and thus becomes melted, so that itscontained mineral values may be successfully recovered from the matteris very small.

My present invention is intended to cor rect all of these wastefuldifficulties and to recover practically all of the mineral valuescontained in fluedust, fines, or concentrates and to do this worksuccessfully and completely at a single operation.

My preferred procedure is to utilize a large converter 1 (illustrated inFig. 1,) composed of heavy metal blocks and preferably having a basiclining 2, composed of magnesite brick or other suitable material. Theflue-dust, fines, or concentrates are then placed in this converter in abody 3 in their natural condition and without previous briqueting orother expense being added to them. The flue-dust may thus be placed inthe converter for treatment either after having been mingled with rawore or with concentrates or with fines, or it may be placed in theconverter by itself and thereafter a capping of ore 4 placed over it, orit may be placed by itself in the converter, providing very carefultreatment is thereafter given it.

I prefer mingling the flue-dust with raw ore of almost any kind before Iplace it in the converter, because it forms a homogeneous mass with theore and cannot float to the surface during the subsequent treatment. Mynext preferred form of treatment would be to place a body of flue-dustin the converter and to then place over it a capping of ore to hold itdown. My least-preferred form of procedure, although this, too, may besuccessfully practiced, would be to place the body of flue-dust in theconverter by itself. Whichever of these three forms of procedure may beadopted, I thereafter run molten matte or slag, preferably the former,into the converter on top of this charge and allow the same to cool orto partially cool, as shown at 5, in order to cement the entire body ofcharge material firmly and securely to the side of the converter. Ifdesired, when the molten matte or slag has been run into the converterthe converter may thereafter be rotated on its trunnions backward andfor- Ward, so as to distribute the molten matte or slag in a layerentirely over the raw charge and to insure that the entire surface ofthe charge shall be thoroughly covered thereby. If desired, while theconverter is thus in a partially-inverted position a mild blast of airmay be delivered through the twyers in order to quicken the cooling andthe cementing action. After this body of charge material has thus beencemented to the side of the converter I deliver on top of it a bodyofmolten matte, which is preferably drawn from a small auxiliarymelting-furnace or cupola or other source of supply, and the con verteris then restored to its upright position, the converting-blast is turnedon, and the converting process is'continued until the entire raw-orecharge has been reduced to the molten condition practically withoutmineral loss and practically without need of car bonaceous fuel solelythrough the heat derivable from the oxidation of the combustibleelements and compounds contained in the charge itself or in the moltenbath. The op eration will be greatly facilitated by utilizing a moltenbath of matte that has beenprocured from the melting of sul'fid ores. Ifdesired, the process may be continued until blister-copper results. Itwill here be explained that by the term cementing is meant the treatmentof the surface of the original charge so as to prevent flotation thereofwhen the molten matte is introduced into the converter.

The charge of raw material and the molten bath may be so predeterminedby analysis that the entire molten bath will flux itself and thatblister-copper may result from one operation and one charge. This,however, is not necessary, because within the spirit and the true intentof my invention other things may be ad dedsuch, for instance, as otherfluxes, ores containing fuel values, ores containing an excess of silicaor silica itself, lime, or iron.

Should the third form of procedure be followed-that is to say, should.flue-dust alone be placed in the converter for treatment and for therecovery of its contained mineral values then great care must beexercised in flowing the molten matte or slag slowly and in smallquantity at a time over the surface of the body of flue-dust, and this.molten matte or slag should be quickly and continuously cooled as itflows in a thin layer over the same, either by a mild blast from thetwyers or by the simple cooling action of the atmosphere. As thespecific gravity of the flue-dust is less than that of the molten matteor slag, the latter should not be run into the converter in considerablevolume at one time, because it would then undermine the fine dust,causing it to float on the surface of the molten matte or slag, and thusdefeating the successful and complete recovery of the mineral values.Moreover, Where flue-dust alone is thus placed in the converter and isthereafter cemented securely to the sides of the converter by means of acementing layer of matte or slag the character of the molten bath withwhich the subsequent converting operation is performed must be somewhatdifferent than where proper percentages of ore constitute an importantproportion of the total charge in the converter.

I may use for practicing my process, a con- IIO constructed for thepurpose with a thicker basic lining and a smaller water-jacketrelatively to each other than those shown in those figures. place in ita large body of raw ore, through which is thoroughly mingled flue-dustfrom which it is desired to recover the values, or I may first place init a body of flue-dust 3 unmixed with fines, concentrates, or ore andthereafter place a capping or .layer of ore 4 entirely over theflue-dust. In either case I In using this vessel I either that itusually requires more time than this I l l l i l l l 1 l l apply theauxiliary heat or fiame from an oil E slag or of fused ore, so that theblast cannot burner 7 over the entire surface of the ore, and I thuspartially fuse the surface, so that it'will cement or hold down themingled ore or finedust or the body of flue-dust with the superimposedbody of ore during subsequent treatment. Thereafter I run any desiredvolume of molten matte procured from an outside source into theconverter. I restore the converter to its upright position and at thesame instant I start the converting process. This quickly melts down anyraw ore, fines, concentrates, or flue-dust, and if the convertingprocess be further continued it will quickly produce blister-copper.

' I prefer the use of the converter illustrated in Fig. 1, which is madeof heavy metal blocks either alone or reinforced with a basic lining.Among its advantages are, first, it absorbs and conserves the heatinstead of dissipating and wasting it, as is the case in any form ofwater-jacketed vessel; second, it does not require special attention orcare in the final stages of the converting process and during the periodwhen the molten contents of the vessel are liable to chill, as is thecase with any water-jacket; third, the expense of an oil-supply and awater-supply is avoided by its use; fourth, the risk of having waternear molten matte or slag is avoided.

The advantages of the water-jacketed converter, especially in themodified form above described, is that one may utilize a furious blastin it to almost any degree ofintensity short of blowing the molten bathout of the vessel without fear of injury to the vessel itself. Oxygen isthe only refining agent for copper, and a supply of oxygen is obtainablemore cheaply from the atmosphere than from any other known source. Itstands to reason, therefore, that the larger the volume of blast and themore quickly it is delivered into the vessel the more rapid will be themelting process and subsequently the refining process to blister-copper.In a vesselsuch as that shown in Figs. 2 and 3 I have successfully useda blast from three and onehalf times to five times the volume that itwould be possible to use safely in any of the various types ofsilica-lined or ore-lined converters that are now in universal use. Ihave so used this volume of blast without injury to the vessel andwithout any special care. In

this manner I have successfully melted raw ore and reduced it toblister-copper 99.4 fine in fifty-five minutes. It is well known tothose conversant with the metallurgy of copper and with the treatment ofcopper ores to reduce a fifty-per-cent. matte in the molten state toblister-copper in the silica or ore lined converter at present used.

My present invention renders the mechanical loss of flue-dustimpossible. The dust is scaled. down to the side of the converter withan impervious layer of congealed matte or reach it and to mechanicallyexpel it from the nose of the converter. Before the ore, concentrates,fines, or flue-dust are melted that is, while the converting action istaking placethey quickly assume a plastic or spongy condition, whichwill not permit the blast to expel it from the nose of the converter andwill not enable it to free itself and float on the surface of the moltenbath. In short, by my present invention it is possible in a singleoperation to reduce every particle of the flue-dust to a moltencondition and thereafter to extract all the contained mineralvalues-such as copper, gold, silver, nickel, cobalt, &c.and this, too,with only the comparatively minute losses that may result fromvolatilization.

Doubtless many modifications will suggest themselves to those skilled inthe art without departing from the spirit of my invention, since That Iclaim is"- 1. The method of recovering mineral values fromfinely-divided value-bearing material, which consists in placing it in aconverter, cementing it therein to the walls of the converter; addingmolten matte; blowing air into the matte and liquefying the dustthereby; substantially as described.

2. The method of recovering mineral values from finely-dividedvalue-bearing ma terial, which consists in placing it in a converter;cementing it therein with a layer of fusible material; addingmoltenmatte; blowing air into the matte and liquefying the dust thereby;substantially described.

3. The method of recovering mineral values from finely-dividedvalue-bearing material, which consists in placing it in a converter;covering it with coarser value-bean ing material cementing the charge;adding molten matte; blowing air into the matte and liquefying thecharge thereby; substantially as described.

4. The herein-described method of recov ering values from finely-dividedvalue-bearing material, consisting in placing a charge of the materialin a converter, cementing the charge therein, introducing a molten bathupon the cemented surface of the charge, and

IIS

then heating the converter and continuing the converting process untilthe charge has been taken up by the bath.

5. The h erein-described method of recovering values from finely-dividedvalue-bearing material, consisting in placing a charge of material in aconverter, introducing the molten material into the charge andpermitting the same to cool to cement the charge within the converter,then introducing a molten bath upon the surface of the cemented charge,and then heating the converter and continuing the converting processuntil the charge has been taken up by the bath.

6. The hereindescribed method of recovering values from finely-dividedvalue-bearing material, consisting in placing a charge of the materialwithin a converter, then introducing molten material upon the surface ofthe charge without undermining the same, then oscillating the converterto distribute the molten material over the surface of the charge andpermitting the same to cool to cement the charge, then introducing amolten bath upon the cemented surface of the charge, and then heatingthe converter and continuing the converting process until the charge hasbeen taken up by the bath.

7-. The herein-described method of recovering values from finely-dividedvalue-bearing material, consisting in placing a charge of material in aconverter, then slowly spreading molten material upon the surface of thecharge without undermining the same and permitting it to cool to cementthe charge, then introducing a molten bath upon the cemented surface ofthe charge, and then heating the converter and continuing the convertingprocess until the charge has been taken up by the bath.

8. The herein-described method of recovering values from finely-dividedvalue-bearing material consisting in placing a charge of material in aconverter, cementing the charge within the converter, then introducingmolten material upon the surface of the charge without undermining thesame and permitting it to cool to cement the charge, delivering a blastof air through the twyers to hasten the cooling and cementing action,then introducing a molten bath upon the cemented surface of the charge,and then heating the converter and continuing the converting processuntil the charge has been. taken up by the bath. v

9. The herein-described method of recovering values from finely-dividedvalue-bearing material, consisting in placing a charge of the materialin a converter, then. placing a layer of coarser fusible material uponthe charge to prevent floating of thelatter, then placing moltenmaterial upon the coarser material and permitting the same to cool tocement the charge within the converter, then introducing the molten bathupon the cemented surface of the charge, and then heating the converterand continuing the converting process until the charge is taken up bythe bath. I

10. The herein-described method of recovering values from finely-dividedvalue-bearing material, consisting in placing a charge of the materialin a converter, then placing a layer of molten material upon the surfaceof the charge without undermining the latter, oscillating the converterto distribute the molten material over the surface of the charge,delivering a blast of air through the twyers to cool the molten materialand cement the charge, then introducing abath of molten material uponthe cemented surface of the charge, and then heating the converter andcontinuing the converting process until the charge has been taken up bythe bath. I 1 1. A step in the recovery of finely-divided value-bearingmaterial, which consists in cementingthe material. in a converter priorto subjecting it to a converting process.

12. A step in the recovery of finely-divided value-bearing material,which consists in placing the material in a converter and treating thesurface thereof so as to prevent flo' tation of the material prior tosubjecting it to a converting process.

'The method of recovering values from finely-divided value-bearingmaterial, which consists in placing a charge of the material in aconverter, treating the surface of the material to prevent flotationthereof, introducing molten matte upon the treated surface of thecharge, and then blowing air into the matte and liquefying thevalue-bearing material.

14. The herein-described method of recovering values from finely-dividedvalue-bearing material, consisting in placing a charge of material in aconverter, introducing a molten bath upon the surface of the charge,said surface of the charge being treated prior to the introduction. ofthe molten bath to pre vent flotation of the material upon the bath, andthen heating the converter and continuing the converting process untilthe charge has been taken up by the bath.

In testimony whereof I have hereunto set my hand.

RALPH BAGGALEY. i/Vitnesses Y AZELLE E. HOBART, WILLIAM M. KIRKPATRICK.

